The Enzyme Database

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EC 1.17.99.3     
Accepted name: 3α,7α,12α-trihydroxy-5β-cholestanoyl-CoA 24-hydroxylase
Reaction: (25R)-3α,7α,12α-trihydroxy-5β-cholestan-26-oyl-CoA + H2O + acceptor = (24R,25R)-3α,7α,12α,24-tetrahydroxy-5β-cholestan-26-oyl-CoA + reduced acceptor
For diagram of cholic-acid biosynthesis (sidechain), click here
Other name(s): trihydroxycoprostanoyl-CoA oxidase; THC-CoA oxidase; THCA-CoA oxidase; 3α,7α,12α-trihydroxy-5β-cholestanoyl-CoA oxidase; 3α,7α,12α-trihydroxy-5β-cholestan-26-oate 24-hydroxylase
Systematic name: (25R)-3α,7α,12α-trihydroxy-5β-cholestan-26-oyl-CoA:acceptor 24-oxidoreductase (24R-hydroxylating)
Comments: Requires ATP. The reaction in mammals possibly involves dehydrogenation to give a 24(25)-double bond followed by hydration [1]. However, in amphibians such as the Oriental fire-bellied toad (Bombina orientalis), it is probable that the product is formed via direct hydroxylation of the saturated side chain of (25R)-3α,7α,12α-trihydroxy-5β-cholestan-26-oate and not via hydration of a 24(25) double bond [5]. In microsomes, the free acid is preferred to the coenzyme A ester, whereas in mitochondria, the coenzyme A ester is preferred to the free-acid form of the substrate [1].
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, CAS registry number: 119799-47-2
References:
1.  Gustafsson, J. Biosynthesis of cholic acid in rat liver. 24-Hydroxylation of 3α,7α,12α-trihydroxy-5β-cholestanoic acid. J. Biol. Chem. 250 (1975) 8243–8247. [PMID: 240854]
2.  Schepers, L., Van Veldhoven, P.P., Casteels, M., Eyssen, H.J. and Mannaerts, G.P. Presence of three acyl-CoA oxidases in rat liver peroxisomes. An inducible fatty acyl-CoA oxidase, a noninducible fatty acyl-CoA oxidase, and a noninducible trihydroxycoprostanoyl-CoA oxidase. J. Biol. Chem. 265 (1990) 5242–5246. [PMID: 2156865]
3.  Dieuaide-Noubhani, M., Novikov, D., Baumgart, E., Vanhooren, J.C., Fransen, M., Goethals, M., Vandekerckhove, J., Van Veldhoven, P.P. and Mannaerts, G.P. Further characterization of the peroxisomal 3-hydroxyacyl-CoA dehydrogenases from rat liver. Relationship between the different dehydrogenases and evidence that fatty acids and the C27 bile acids di- and tri-hydroxycoprostanic acids are metabolized by separate multifunctional proteins. Eur. J. Biochem. 240 (1996) 660–666. [PMID: 8856068]
4.  Dieuaide-Noubhani, M., Novikov, D., Baumgart, E., Vanhooren, J.C., Fransen, M., Goethals, M., Vandekerckhove, J., Van Veldhoven, P.P. and Mannaerts, G.P. Erratum report. Further characterization of the peroxisomal 3-hydroxyacyl-CoA dehydrogenases from rat liver. Relationship between the different dehydrogenases and evidence that fatty acids and the C27 bile acids di- and tri-hydroxycoprostanic acids are metabolized by separate multifunctional proteins. Eur. J. Biochem. 243 (1997) 537. [PMID: 8856068]
5.  Pedersen, J.I., Eggertsen, G., Hellman, U., Andersson, U. and Björkhem, I. Molecular cloning and expression of cDNA encoding 3α,7α,12α-trihydroxy-5β-cholestanoyl-CoA oxidase from rabbit liver. J. Biol. Chem. 272 (1997) 18481–18489. [PMID: 9218493]
6.  Russell, D.W. The enzymes, regulation, and genetics of bile acid synthesis. Annu. Rev. Biochem. 72 (2003) 137–174. [PMID: 12543708]
[EC 1.17.99.3 created 2005]
 
 


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